The old one about "getting a hot meal inside you". What - apart from immediate warmth - does a hot meal provide that a cold one doesn't? Are there any significant temperature-based properties that make hot better?
Cooking some foods breaks down the tough cellular membranes which we cannot digest allowing us to absorb the nutrients better - I remember a study on carrots and how they release more carotene when briefly cooked.
However, some nutrients are destroyed by applying heat so it's swings and roundabouts really. Par-boiling or steaming is better since the goodness doesn't leach out as much in veg.
The impotant difference is probably hygeine.....hot meals tend to have less pathogens in them, provided they are hot, not motorway-cafe warm. Some nutrients are only released when heated. This is true of collagen and glucosamine to an extent, which are otherwise hard to digest. There is a lot of evidence that metal cooking pots can increase iron content in the diet.
Aside from that cooking can be bad. Many of the caramelised compounds from cooked meat are carcinogenic.